Electronic structure, magnetic properties, and magnetostructural transition in Tb(5)Si(2.2)Ge(1.8) from first principles

TitleElectronic structure, magnetic properties, and magnetostructural transition in Tb(5)Si(2.2)Ge(1.8) from first principles
Publication TypeJournal Article
Year of Publication2011
AuthorsPaudyal D, Mudryk Y, Pecharsky VK, Gschneidner KA
Journal TitlePhysical Review B
Volume84
Pages014421
Date Published07
ISBN Number1098-0121
Accession NumberWOS:000293180200009
Abstract

The electronic structure and magnetic properties of Tb(5)Si(2.2)Ge(1.8) have been studied from first principles electronic structure calculations. The total energy of the ferromagnetic (FM) orthorhombic [O(I)] Tb(5)Si(2.2)Ge(1.8) is lower than the total energy of the FM monoclinic (M) Tb(5)Si(2.2)Ge(1.8), indicating that the FM O(I) is the ground state structure of Tb(5)Si(2.2)Ge(1.8). Because of a strong 4f-5d exchange, the splitting of 5d bands of Tb atoms in the FM O(I) Tb(5)Si(2.2)Ge(1.8) is greater than that in the FM M Tb(5)Si(2.2)Ge(1.8), giving rise to higher 5d moments in the former. The magnetostructural transition temperature, T(M), and the isothermal magnetic entropy change, Delta S(M), have been calculated by coupling the parameters obtained from the first principles to the magnetothermodynamic models. Both T(M) and Delta S(M) are in good agreement with reported experimental values. The magnetic entropy change increases with decreasing magnetostructural transition temperature, which indicates a pathway toward tuning the magnitude of the magnetocaloric effect.

DOI10.1103/PhysRevB.84.014421